Process for forming metal alloys



Oct. 18,1932. J. o. BETTERTON PROCESS FOR FORMING METAL ALLOYS Filed March 16. 1929 auvcutozi A Patented 0a. 1a, 1932v UNITED. STATES PATENT OFFICE JESSE OATMAN IBETTEBTON, OF OMA HA, NEBRASKA, ASSIGNOR TO AMERICAN SMQELTING" AND REFINING COMPANY, OF NEW YORK, N. Y., A CORPORATION OF NEW JERSEY PROCESS FOR FORMING METAL ALLOYS Application filed March 18, 1929. Serial No. 347,508.

This invention relates to a method of producing metal alloys and, more particularly,

to a new and improved method of forming a metal alloy of the type commonly known as shot metal. The invention provides specifically for introducing arsenic in the desired percentages into antimonial lead whereby the desired properties are imparted thereto.

In treating antimonial lead to render the same'suitable for shot metal it is frequently desirable to introduce arsenic in amounts up to 2 or 3%. This may conveniently be accomplished by utilizing black dust which contains certain arsenic oxides. It is also necessary to introduce a reducing agent for reducing the higher oxides of arsenic to the lower oxides and to metallic arsenic which may be readil absorbed by the lead to form the desired 'al 0y.

The invention further consists in the new and novel features of operation and the new and original arrangements and combinations of steps in the process hereinafter described and more particularly set forth in the claims.

Although the novel features which are believed to be characteristic of this invention will be particularly pointed out in the claims appended hereto, the invention itself, as to its objects and advantages, the mode of its operation and the manner'of its organization ma be better understood by referring Qtothe ollowing description taken in con nection with the accompanying drawing forming a part thereof, in which the figure is a side elevation partly in section ofan apparatus which may be employed forcausingto a temperature ,of 900 to 1000 F. and the required percents of reducing agent such as' coal, coke or 01'. er carbonaceous material, together with the arsenic-bearing material is' kettle for containing the molten metal. The

thoroughly incorporated therewith. This may be accomplished by employing 'a mixing device of the type illustrated in the accompanying drawing, in which 10 represents a kettle may be heated from any convenient source not shown, and is supported byesuitable beams 11. A stirring device comprising a rotating paddle L2 is mounted upon a transverse beam 13 in a suitable position to be immersed in the metal when the beam is supported across the rim of the kettle. The pad (110 may be rotated by shaft 15 which is asso ciated with a suitable source of power, not shown, and drives shaft 16 carrying said paddlethrough suitable gears represented at 17. Paddles 12 are suitably inclined to impart a downward and outward motion to the metal thereby causing the metal to rapidly rotate in the kettle and imparting a well defined vortex 20 to the center portion thereof. The added ingredientsare applied to this vortex and are rapidly drawn into the body ofthe bath and are disseminated throughout the entire mass. By drawing the reagents down into the bath surface oxidation and volat-ilization is largely prevented as will be pointed out. In carrying out this process thelantimonial lead is placed in kettle 10 and heated to a temperature of between 850 and 1000 F. The stirring mechanism is then started therebycreating a well defined vortex in the center of the bath. To this vortex predetermined quantities of finely. divided carbonaceous reducing-agents and black powder are'added at intervals and are immediately drawn into the center of the bath and incorporated with the antimonial lead. A portion of the arsenic will be absorbed by the lead,f another portion will be volatilized and the rest remains in the slag or dross. The volatilized portion may be recovered by applying a suitable hood 21 over-the kettle. This hood collects the volatilized arsenic which may be led through a suitable pipe, not shown, to a. collectingvmeans, such as a baghouse. The slag may be separately treated for the recovery of the va uable constituents contained therein.

As a specific example of the method in m mixed with 18% fine petroleum coke was stirred into the antimonial lead in charges of 600 lbs; between skimming operations The bath was heated to a temperature in excess of 900 F. and 200 lbs. of the above mixture were applied thereto. When the tem-' perature of-between 900 and 950 F; was obtained, an additional 200 lbs. of the niix:

ture were added directly to the vortex within a period of some 10 minutes. The mass was then stirred for approximately 20 to 25 minutes to change the black dust into asemipasty slag. 200 additional lbs. were then charged into the vortex and the stirring continued until the black dust thus added was changed to a pasty slag. After this occurred the mixing was stopped and the slag removed and the aboveprocess repeated until the required 7400 lbs. of black dust had been added. The total time for stirring the 600 lb. charge, including the 10 to 15 minutes required for skimming the slag, is approximately 1 hour and it was found that the arsenic content of the bath was increased at the rate of -.15% of arsenic per hour. The total time for addin the 7400 lbs. of black dust, including the srimming time, was approximately 19 hours.

It was found that approximately of the total arsenic was absorbed'into the lead,

' 26% remained in the slag and the remainder is added in 200 1b. charges as above'described, inasmuch as this amount is rapidly drawn into the bath and removed from the surface.

The major part of the volatilizing occurs immediately above the vortex. Although it was found that a 600 lb. charge could be conveniently handled before skimming, this amount depends upon the vortex andthe' rapidity with which it may be incorporated in the bath. By producing a larger vortex it is apparent that larger charges can be utilized and the total time of operation can be accordingly decreased. c

The volatilized arsenic is recovered in a baghouse as'arsenious oxides or compounds thereof and may again be returne d to the treatment kettle for further use. During the operation, dross or slag rises-to the top of the lead, but is again drawn under by the vortex in the mixing machine,wherebyvola tilization'is retarded. It is obvious that the operation maybe continued until an amount of slag is formed which is sufficiently great so that a large portion thereof remains on as above described. The metal resulting from the above operation was found to contain in addition to the lead, 12.8% of antimony and 2.2% of arsenic. v

The above described operation provides forf'efiiciently adding arsenic to antimonial lead and for rapidly reducing the arsenic oxides and causing them to be incorporated into the bath. Since the arsenic oxides and the reducing agent are both in a finely divided condition and in immediate contact, it is obvious that the reduction absorption of the arsenic inthe bath Wlll be greatly accelerated. Although/certain novel features of the inand consequent.

vention have been shown and described and i be understood that various omissions, substitutions and changes in the several steps of the process and in its operation may be made by those skilled in the art without departing from the spirit of the invention.

What is claimed is:

l. The process of introducing arsenic into antimonial lead, which comprises heating a bath of antimonial lead to a temperature above 850 F; rapidly stirring said bath to produce a. vortex therein, periodically applying arsenic oxide to ether with finely di vided reducing materia to said vortex until the arsenic oxide forms a pasty slag, skimming the slag and continuing the addition of said oxide and reducing agent until the required amount of arsenic has been incorporated in the lead.

2. The process of introducing arsenic into lead, which comprises melting a bath of lead rapidly stirring said bath to produce a vortex therein, and applyingarsenic containing material to "said vortex until the required amount of arsenic has been incorporated in the lead.

3. The process of introducing arsenic into antimonial 1ead to form shot metal, which comprises heating a bath of antimonial lead to a temperature. above 900 F. rapidly stirring said bath to produce a vortex therein, applying black dust together with finely divided reducing material to said vortex until the arsenic oxide forms a pasty slag, skim ming the slag andv continuing the addition of said black dust and reducing agent until the required-amount of arsenic has been incorporated in the lead.

- In testimony whereof I have hereunto set myhand. a .JESSE OATMAN 'BETTERTON.

the surface. At this point it is advisable to interrupt the operation and remove the slag 

